Of all the forces in Hell, few are so ubiquitously known as the Nightmare Imp. Small things, they find it easy to slip onto the material plane and steal into human settlements. All too many people know the sensation of the waking nightmare, a memory of paralysis as the creature sits upon their chest and wracks them with nightmares. Then it slips away, invisible, to torment another, or, perhaps, to return night after night until a poor soul dies of its troubled sleep.

Magic Resistance. The imp has advantage on saving throws against spells and other magical effects.

Projected Nightmares. A nightmare imp can use the minor illusion cantrip at will, except its effects can include sound, smell, and light. Its spellcasting attribute is Charisma and its save DC is 12.

Nightmare Ride. When a Nightmare Imp sits on the chest of a sleeping creature, the sleeper is wracked with horrific and intense nightmares. When it awakens, instead of losing any levels of exhaustion it had due to resting, it gains a single level of exhaustion – though it still gains any other benefits of resting, such as regaining hit points and recovering spells. A dispel evil, remove curse, or dispel magic spell removes all levels of exhaustion a nightmare imp has afflicted on a character.

Actions

Bite. Melee/Range Weapon Attack: +5 to hit, reach 5 ft., one creature. Hit: 6 (1d6 + 3) bludgeoning damage. If the target is a creature capable of dreaming, it must succeed on a DC 12 Constitution saving throw or fall asleep for one minute, until it takes damage, or until someone uses their action to physically shake the creature awake.

Invisibility. The imp magically turns invisible until it attacks or until its concentration ends (as if concentrating on a spell). Any equipment the nightmare imp wears or carries is invisible with it.